Reinforcing iron



Dec. 8,197) I R 3,545,158

REINFORCING IRON Filed April 23, 1968 United States Patent Office 3,545,158 Patented Dec. 8, 1970 Int. Cl. E04c /0]; E04f 13/12 US. Cl. 52-726 1 Claim ABSTRACT OF THE DISCLOSURE Reinforcing iron, a portion of which is twisted into a spiral insuring a better fastening in the concrete and allowing the assembling of two reinforcing irons by overlapping one of the spiral with that of the other iron.

This invention relates to reinforcing elements for concrete.

During the erection of reinforced concrete structures, one of the longest operations is the formation of the reinforcements by joining together reinforcing elements using welded joints together with fixing members.

A main object of the invention is to provide a concrete reinforcing element whereby an eflicient anchorage in the concrete is obtained and which, moreover, enables the reinforcements to be easily assembled with excellent rigidity. It will be observed that the elements are assembled without welding, which makes it possible to use steel of high mechanical resistance obtained by thermal treatment, which resistance would be destroyed by welding.

For reasons of economy these reinforcing elements are generally made of iron or steel, it will be understood that the use of other metals, as well as plastic, glass and other materials, is Within the scope of the invention.

According to the invention, reinforced concrete includes a reinforcing element of which at least a portion is twisted into a spiral.

In order that the invention may be more fully understood, some embodiments in accordance therewith will now be described, by way of example, with reference to the accompanying drawings in which:

FIG. 1 is a view showing the assembly of two reinforcing elements of the invention;

FIG. 2 is a section along the line IIII of FIG. 1;

FIG. 3 is a section along the line III-III of FIG. 1;

FIG. 4 is a view showing the assembly of two elements of the invention forming a branch;

FIG. 5 is a schematic view showing the formation of a pulling loop on a reinforcing element of the invention; and

FIG. 6 is a schematic view showing the fixing of two intersecting elements by means of a third element of the invention.

Referring to the drawings, the reinforcing element of the invention is a round rod 1 twisted into a spiral in such a manner that the axis of the spiral, the locus of which is represented in FIG. 2 at 0, remains Within the rod 1.

When the two elements 1 and 1a are assembled by twisting the spirals of the elements to form a composite element 2, this arrangement of the diameter of the spiral to be less than twice the diameter of the twisted rod 1, necessitates an increase in the diameters of the spirals and thus ensures better gripping due to the resilience of the elements. It is clear that the threads of the spirals of the assembled elements must be identical, but the diameters of the rods need not necessarily be the same.

This type of spiral element moreover ensures a fastening in the concrete which is greatly superior to that obtained with known notched steel elements.

When it is desired to form a branch (FIG. 4), on an element 1, it is sufficient to take an element 1b whose end 3 is bent and has its spiral overlapping with that of the element 1 at the desired place.

For manufacturing prestressed concrete, a pulling loop 4 (FIG. 5) can be formed by bending back on itself an element 1c and overlapping the spiral of the bent back portion with that of the remainder of the element.

Furthermore, when it is desired to hold in place two intersecting elements 1 and In (FIG. 6) it is sufiicient to overlap the spiral of a precurved element 1d with the spirals of the elements 1 and 1a.

The twisted spiral element of the invention enables composite structures and joins to be easily formed and these can, moreover, be reinforced by a coating of abrasive powder, by knurling the elements, or by producing friction by means of other spiral elements which preferably have a smaller thread than those of the assembled elements.

It will be observed that these composite elements and assemblies themselves ensure excellent electrical equipotential connections of the reinforcements formed.

The invention is not limited to the embodiments described and shown, but covers all variants thereof. In particular the elements can have any form, such as semicircular, elliptical, square, etc.

What is claimed is:

1. Preformed reinforcing elements for reinforced concrete comprising an elongated rod preformed into a helix having a constant pitch, a constant helix angle with respect to the longitudinal center line, and a constant diameter for the convolutions making up the helix, said rod, in the relaxed state, having the locus of the axis of the helix within the reinforcing rod periphery, a second elon gated helical rod having helix characteristics identical to the first said rod, the respective helixes of the two rods being intertwined along portions of the two rods, thereby joining said two rods along said portions, each of said rods along said joined portions having its respective locus of the axis of the helix exterior of the rod periphery, the diameter of the convolutions being slightly increased and expanded along said joined portions so that the re siliency of the two helical rods cause the rods to grip one another, whereby the two preformed elements may be spliced to one another at any location along their longitudinal lengths.

References Cited UNITED STATES PATENTS 741,347 10/1903 Lamb 287-77 877,734 1/1908 Reuther 52-733 881,834 3/1908 Vamey 52-736 1,551,863 9/ 1925 Berry 52-737 1,692,505 11/ 1928 Hoffman 52-736 1,890,023 12/1932 Schroder 52-445 2,376,761 5/1945 Fahy 52-738 2,611,945 9/1952 Simonsson 52-727 3,023,037 2/ 19'62 Sandor 287-77 2,947,504 8/ 1960 Ruhlman 57-1'45 3,274,846 9/ 1966 Forster 57-145 3,283,492 11/ 1966 Little 57-145 HENRY C. SUTHERLAND, Primary Examiner US. Cl. X.R. 

